Correlation between changes in corneal asphericity and progression of keratoconus in children

Clinical relevance Early detection of keratoconus (KC) progression and timing for retreatment. Background Q value (coefficient of corneal asphericity) reflects the shape of the cornea, its refractive power, and spherical aberration. In this study, we aimed to analyze the correlation between changes in Q value and progression of KC in children. Patients and methods In this retrospective cross-sectional study, clinical data of 18 eyes of nine children that were diagnosed as bilateral progressive KC (four boys, five girls: mean age of 11.3±1.6 years) were extracted from a Scheimpflug camera (Pentacam) for analysis before (baseline) and annually after bilateral transepithelial corneal collagen cross-linking (TE-CXL) up to 5 years of follow-up. Results At all follow-up visits up to 5 years, Kmax improved significantly (mean change at 5 years was 1.6 D) (P<0.001); uncorrected visual acuity and best-corrected visual acuity showed significant changes at all follow-up visits (P<0.001). In seven (38.8%) eyes, KC had progressed by more than 1.0 D by the last follow-up visit, despite corneal cross-linking. In the last visit, there was a significant negative correlation between mean Q value and Kmax in both 6 and 8 mm anterior corneal zones (Pearson correlation coefficient, r=−0.847, P<0.001, r=−0.605, P<0.001, respectively). Conclusion There is significant negative correlations between changes in corneal asphericity and progression of KC in children, which could be considered with other parameters in early detection of disease progression and timing for retreatment after transepithelial corneal collagen cross-linking.